Physiological feedback systems and methods

ABSTRACT

The disclosed physiological feedback systems and methods assist with assessing, monitoring and/or treating a patient experiencing a cardiac arrest event. The systems and methods receive multiple inputs and are continuous and/or iterative during a treatment session to provide physiological state trends of the patient. An index of the physiological state of the patient can be derived and confounders, and/or their effects, can be identified, and/or removed, from the index. Additionally, the systems and methods can assist with determining ischemic injury in a patient based on cerebral tissue oxygenation and/or other physiological data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/960,324, filed on Apr. 23, 2018 and titled “Physiological FeedbackSystems and Methods,” which claims the benefit of and priority to U.S.Provisional Patent Application Ser. No. 62/488,678 filed on Apr. 21,2017 entitled “Physiological Feedback System and Method to SupportCardiac Arrest Resuscitation Management,” and U.S. Provisional PatentApplication Ser. No. 62/489,029 filed on Apr. 24, 2017 entitled “CPRFeedback using Tissue Oxygenation Technologies,” all of which areincorporated herein by reference in their entirety.

BACKGROUND

During cardiac arrest, a patient is pulseless and in need of immediatelife-saving treatment. Often, the first response is to beginadministering cardiopulmonary resuscitation (CPR) to the patient tomechanically force blood through the patient. This mechanicalcirculation can move the patient's blood in an attempt to provide oxygento the patient's organs to help keep the patient alive. To assist withthe life-saving effect, one or more parameters of the administered CPRcan be altered in an attempt to increase the efficacy of the CPR.

For patients in cardiac arrest, the current treatment protocol oftenrequires that rescuers achieve a return of circulation prior totransporting the patient to a hospital. This requirement increases thelikelihood that the patient is stable and/or ensuring the patient has areasonable expectation of recovery from potential further treatment theylater receive at the hospital. While the return of circulation is aclear threshold, it does not account for other potential factors thatcan indicate a likelihood of a positive clinical outcome for thepatient.

There exists a need for physiological feedback systems and methods thathelp rescuers improve clinical outcomes for cardiac arrest patients.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example block diagram of a physiological feedback system.

FIG. 2 is an example block diagram of another physiological feedbacksystem.

FIG. 3 is an example block diagram of a further physiological feedbacksystem.

FIG. 4 is an example physiological feedback method.

FIG. 5 is a further example physiological feedback method.

FIG. 6 is another example physiological feedback method.

FIG. 7 is yet another example physiological feedback method.

FIG. 8 is an example method of detecting the presence of Return ofSpontaneous Circulation (ROSC).

FIG. 9 is another example physiological feedback method.

FIG. 10 is still another example physiological feedback method.

DETAILED DESCRIPTION

Physiological feedback systems and methods are described herein. Thedescribed systems and methods assist rescuers, or others, in assessingthe physiological state of the patient, and/or assessing the course ofthe patient's physiologic state over a patient care event, such as aresuscitation effort. For rescuers, the systems and methods can assistwith predicting the Return of Spontaneous Circulation (ROSC), assessingthe hemodynamic stability of the patient who has achieved ROSC forpotential decline, and/or determining eligibility of the patient formore intensive resuscitation procedures that are only consideredappropriate for a carefully-selected subset of patients. The describedsystems and methods can allow the rescuer to continuously monitor thephysiological state of the patient and the effects of treatmentsperformed thereon. The “whole picture” monitoring provided the rescuerscan assist in determining the stability and/or transportability of thepatient. Rather than relying on a singular or narrow criterion, therescuer, and/or others, can be provided a comprehensive patientmonitoring/treatment output from which further monitoring and/ortreatment decisions can be made. Additionally, this iterative/continuouspatient monitoring of the patient's physiological state can assist withassessing potential physiological damage of the patient caused by theevent they are experiencing. This damage assessment can also be used toassist with determining further patient treatment and/or monitoring.

The systems and methods can use tissue oximetry and/or capnography datato provide feedback regarding monitoring and/or treatment of a patient.The feedback can include instructions to, and/or can be used to, alter,or otherwise change, the administration of treatment to the patient. Forexample, of one or more parameters of cardiopulmonary resuscitation(CPR) administration can be altered/changed based on the collectedand/or analyzed tissue oximetry and/or capnography data. The tissueoximetry and/or capnography data can be used to derive an index to aidin the monitoring and/or treatment of the patient. Additionally, thetissue oximetry and/or capnography data can be used to determine theReturn of Spontaneous Circulation (ROSC) and/or predict its likelihood.Further, the treatment and monitoring data can be correlated, such as byusing the tissue oximetry and/or capnography data, to monitor thephysiological effect of one or more treatments administered to thepatient.

Further, the systems and methods described herein can identify potentialconfounders and their effects on the physiological state of the patient.Confounders are external influences, such as environmental influences,patient treatment influences, patient observations and/or other externalinputs to the patient, that can obscure or influence the patientmonitoring and/or treatment. Example confounders can includeadministration of medication that causes temporary changes in one ormore physiological parameter measurements, unexpected patientobservations, environmental factors and/or other inputs that can obscurea physiological state of the patient and/or the monitoring/treatment ofthe patient. The described systems and methods provide continuous anditerative patient monitoring that can assist with discriminatingconfounders and their influence in the patient monitoring. Confounders,and/or their effects, can be identified in the patient monitoring due toreceived information, such as patient physiological data, and/or by userinput, such as observations and/or medication administrations. Inaddition to the multiple inputs that are processed and/or analyzed aspart of the index, multiple confounders can also be accounted for.Additionally, both the confounders and/or other patient data can beaccounted for in a time domain, allowing for the index to includetemporal information that can assist with patient treatment and/ormonitoring information.

FIG. 1 is an example patient treatment/monitoring system 100 thatincludes a medical device 110 that can be connected to and/or incommunication with a sensor(s) 120, other patient monitoring and/ortreatment devices/systems 130, 140, and/or a remote location 150. Themedical device 110 can receive patient data from one or more sources andcan provide regional tissue oximetry (rSO2) data—which describes theaggregate oxygenation state of the blood within a certain region oftissue—along with related data, to assist with patient monitoring and/ortreatment. Using the patient data, the medical device 110 can displayand/or provide information regarding the patient status. The medicaldevice 110 can provide an increased accuracy and/or more comprehensivepatient status by relating various patient physiological parameter andtreatment data. In this manner, changes to the patient's physiologicalstate can be more accurately assessed as an actual change in thepatient's state or as a temporary change based on a treatment and/orother cause. The treatments and/or other causes are confounders,elements and/or inputs that cause, directly and/or indirectly, changesin the patient physiological data that obscure changes in the patientphysiological data due to actual changes in the patient's physiologicalstate. Accounting for, noting and/or removing the confounder effects onthe patient physiological data allow for an increased accuracy in suchdata for assessment, monitoring and/or treating the patient. Forexample, administration of certain medications can cause a temporaryand/or immediate increase in the CO2 levels in the patient's blood, andthus the end-tidal CO2 values measured by capnography. Such change inthe physiological parameter data, capnography, of the patient, due tothe medication administration, is short-term and/or temporary. Arescuer, device and/or system can monitor the capnography data and maymisinterpret the temporary increase in CO2 production as an indicator ofpatient improvement, and consequently may administer further patientmonitoring and/or treatment based on this interpretation. By relatingthe physiologic parameter and treatment data, the system 100 can helpthe rescuer and/or device avoid misinterpreting such a change in one ormore patient physiological parameters as an actual change in the patientstate, rather than just an artifact of the medication administration.

The medical device 110 can include an input 112, a monitoring module 114and/or a sensor(s) 116. To collect and/or receive patient data, themedical device can include the sensor(s) 116 and/or can communicate withother devices and/or systems, such as the sensor(s) 120, a chestcompression machine 130, a defibrillation device 140, the remotelocation 150 and/or other external devices and/or systems. The collectedand/or received patient data can include oximetry data, such as cerebraland/or other tissue oximetry data, and/or can include capnography data.The oximetry and/or capnography data can be analyzed and/or evaluated bythe medical device 110 in correlation with the other received patientdata, such as patient physiological and/or treatment data. Additionally,the medical device 110 can receive input 112 from a user and/or anexternal device/system. The input 112 can include patient treatmentand/or observation data. For example, the input 112 can include dataregarding medication administration, such as a medicationidentification, dosage, and/or other administration data and/or caninclude patient observation data, such as patient gasping, consciousnessand/or purposeful movement, that can be provided by a user and/ordevice/system. Additionally, the input 112 can provide data regardingthe weighting and/or importance of one or more of components of thepatient data, such as a particular physiological parameter. Such inputcan be provided by a user, device and/or system. The medical device 110can provide an output of the collected patient data that correlates theinput and/or analyzed/evaluated oximetry/capnography data with otherphysiological and/or treatment data. In an example embodiment, thiscorrelation can indicate that a change in a physiological parameter is aresult of a change in the patient's physiological state or as a resultof a confounder, such as a medication administration and/or a patienttreatment.

The process of receiving and analyzing patient data can be a continuousand iterative process. This can allow the analysis and/or evaluation ofpatient data performed by the medical device 110 to be refined aspatient treatment and/or monitoring continues. That is, eventsthroughout the patient monitoring and/or treatment session can be usedto refine analysis and/or evaluation of additional collected and/orreceived patient data to assist with patient monitoring and/ortreatment. Using the repeated/continuous and/or iterative analysisand/or evaluation of patient data, the medical device 110 can providetrend data for one or more physiological parameters of the patient. Thetrend data can assist with and/or guide additional, or further, patientmonitoring and/or treatment. Additionally, the trend data can reduceimmediate and/or temporary changes to patient physiological parameterdata so that decision making by a user, device and/or system can bebased, at least in part, on trends in the data rather than solely on areal-time value of the data.

The medical device 110 provides an output that is a synthesis of patientdata and/or inputs from one or more users, devices and/or systems. Inthis manner changes in the patient data can be evaluated based on animportance, effect, weight or other qualifier of one or more of thecomponents of the patient data and/or the received inputs. That is,changes in the patient data can be validated with, and/or correlated, tochanges in one or more components of the patient data and/or inputs. Forexample, a change in a first component of the patient data can becorrelated to a change in a second component of the patient data and/oran input. Based on the correlation, the change in the first component ofthe patient data can be assessed and/or evaluated as a change in anactual patient state or can be assessed/evaluated as a change based onanother factor, such as a change in treatment and/or administration of amedication. In this manner, the effect of changes in treatment of thepatient can be evaluated for an associated impact on the physiologicalstate of the patient.

Additionally, the multiple inputs to the medical device 110, to be usedin generating the output, can include temporal data. This can allow theinputs, and/or their effects on the physiological state of the patient,to be evaluated spatially. That is, the timing of various treatmentsand/or their effects on the patient's physiological state can beaccounted for in the generated output by the medical device 110.

The monitoring module 114 can receive and/or collect patient physiologicdata, including oximetry and/or capnography data, such as by thesensor(s) 116. Oximetry and/or capnography data can be tracked by themedical device 110 during the patient monitoring/treatment session andcan provide data regarding the physiological state of the patient. Whilethe real-time values of oximetry and/or capnography data can fluctuate,the trend of the oximetry/capnography data can be indicative of thetrend of the patient physiological state. For example,oximetry/capnography values can be repeatedly changing, however, whenanalyzed/extracted as a trend, the oximetry/capnography trend canindicate changes to the patient physiological state over longerincrements of time. The physiological parameters of oximetry and/orcapnography are not only indicative of the patient physiological state,but are also parameters that exhibit correlation with each other. Thatis, increases in tissue oximetry are often accompanied by increasedcapnography measurements, as increased tissue oxygenation status duringCPR is typically associated with increased blood flow which also causesincreases in expired CO2. This correlation/relationship can allow thetwo parameters to validate each other and can also assist in validating,evaluating and/or assessing changes in other physiological parameters,such as changes in the patient electrocardiogram, blood pressure and/orother physiological parameters.

The medical device 110 can optionally include one or more sensors 116 tocollect and/or receive patient data, such as physiological parameterdata. Alternatively, or additionally, the medical device can beconnected to and/or in communication with other sensors 120, othermedical devices 130, 140, and/or one or more remote locations 150 toreceive/collection patient data from. The collected and/or receivedpatient data can be analyzed, evaluated and/or correlated by the medicaldevice and/or other devices, to provide a comprehensive output that canassist with patient monitoring and/or treatment by a user, device and/orsystem. The comprehensive output can, or can assist with, identificationof confounders in the patient data, such as changes in the patient dataattributable to factors other than a change indicative of an improvementor a decline in a trend of the physiological state of the patient, suchas in response to a treatment or lack thereof.

The output of the medical device 110 can assist with treatment and/ormonitoring of the patient by a user and/or other devices/systems, suchas 130, 140, 150. In an example, a user can be administeringcardiopulmonary resuscitation (CPR) to a patient. The output of themedical device 110 can be, or can be used to assist with, CPR feedback.The user can receive the CPR feedback and can adjust, and/or receiveinstructions to adjust, the administration of the CPR to the patient toassist with increasing the efficacy of the administered CPR. While theCPR feedback can include comparison of the administered CPR to a CPRadministration model, such as including a range of preferred chestcompression depth and/or rate, the CPR feedback provided by, or basedon, the output of the medical device 110 also compares, or accounts, forthe effectiveness of the administered CPR by monitoring and/or analyzingtrends in the collected/received patient data. For example, theeffectiveness of the CPR and the feedback based thereon can bedetermined using one or more physiological parameters, such as tissueoximetry and/or capnography data. The tissue oximetry and/or capnographydata can provide insight to the levels, or degree, of blood flowoccurring in the patient which can be an indication of changes in thepatient's physiological state and/or an indication of the effectivenessof administered treatments, including CPR for example or othertreatments alone or in combination with administered CPR. If the outputof the medical device 110 indicates that the patient's physiologicalstate is declining despite the administration of the CPR, the medicaldevice 110, the user, and/or other device/system can alter, and/orinstruct/cause to be altered, the administration of the CPR to increasethe effectiveness of the administered CPR treatment with regards to thepatient's physiological state. Alteration of the administered CPR caninclude relocating the point, or area, on the patient to whichcompression force is being applied in the administration of CPR. Therelationship between body surface landmarks and underlying vital organstructures is not identical between people, so repositioning of thelocation at which CPR compression force is being applied may facilitatean increase in the effectiveness of the administered CPR based on thepatient's individual anatomy. Other alterations can include altering thedepth, rate and/or other parameters of the administered CPRcompressions. Further, much like the output of the medical device 110,such treatment feedback, such as CPR feedback, can also be an iterativeprocess, with additional treatment alterations and/or additionsinstructed, or administered, based on the output of the medical device110.

In addition to receiving information, such as patient data, from the oneor more external users, devices and/or systems, the medical device 110can also provide information, such as the output, to the external users,devices and/or systems. In the example shown in FIG. 1, the medicaldevice 110 can communicate with other treatment/monitoringdevices/systems, such as the chest compression machine 130 and/ordefibrillation device 140. The chest compression machine 130 and/or thedefibrillation device 140 can receive the output, or otherinformation/instructions, from the medical device 110, which can alterthe monitoring and/or treatment of the patient based on the receivedoutput, or other information/instructions.

The chest compression machine (CCM) 130 can administer chestcompressions, such as part of a CPR treatment, to a patient and caninclude sensors 132, such as for monitoring the administration ofcompressions by the chest compression machine 130 and/or one or morephysiological parameters of the patient. Additionally, or alternatively,the CCM 130 can receive patient physiological and/or other data from theoptional sensor(s) 120. The chest compressions administered by the CCM130 can have specific characteristics, including a depth of compression,a velocity of the administered compression, and/or a rate at whichcompressions are administered. Further, the CCM 130 can also administeractive decompressions by actively lifting the patient's chest. Thesensors 132 can transmit information to the medical device regarding theoperation of the CCM 130 and/or the physiological state of the patient.The CCM 130 can also receive instructions from the medical device 110 toalter the administration of compressions by the CCM 130. The receivedinstructions can automatically cause the CCM 130, and/or require atleast some user input to cause the CCM 130, to alter the administrationof compressions and/or active decompressions to the patient.

The CCM 130 can also communicate with one or more remote locations 150.The communication can include sending and receiving of informationand/or instructions. That is, the remote location 150 can receive datafrom the CCM 130, such as sensor 132 data, and/or can transmitinstructions to the CCM 130, such as to alter administration oftreatment by the CCM 130.

The defibrillation device 140 can administer defibrillation therapy,such as electrical shocks, to the patient and can include a sensor(s)142, such as for monitoring one or more physiological parameters of thepatient. Additionally, or alternatively, the defibrillation device canreceive patient physiological and/or other data from the optionalsensor(s) 120. The defibrillation device 140 can transmit and/or receiveinformation with the medical device 110. The information transmitted tothe medical device 110 can include patient physiological informationand/or patient treatment information, such as information regardingadministered defibrillation therapies. The information received by thedefibrillation device 140 can include the output, and/or instructions,from the medical device 110. The output, and/or the instructions, fromthe medical device 110 can alter patient monitoring and/or treatment bythe defibrillation device 140. In an example, the medical device 110 cantrack the administration of defibrillation shocks to the patient and theresulting effects of the administered treatment. The output of themedical device 110 can be used by, and/or include instructions for, thedefibrillation device 140 to provide an altered, or different, treatmentto the patient based on the previous treatment and/or the physiologicalstate trends of the patient.

The defibrillation device 140 can also communicate with the one or moreremote locations 150. The communications can include sending andreceiving of information and/or instructions. That is, the remotelocation 150 can receive data from the defibrillation device 140, suchas sensor(s) 142 data, and/or can transmit instructions to thedefibrillation device, such as to alter the administration of treatmentby the defibrillation device 140.

The remote location 150 can communicate with the medical device 110and/or other devices and/or systems that are used in monitoring and/ortreating the patient. The medical device 110 and/or other devices and/orsystems can receive data and/or instructions from the remote locationand can provide data, such as patient physiological and/or treatmentdata, to the remote location 150. The remote location 150 can alsoprovide additional patient information, such as previous treatmentand/or monitoring history to other users, devices and/or systems, suchas the medical device 110. The remote location 150 can be a user, deviceand/or system external from the medical device 110, such as a mobilecomputing device 152, a medical director 154, a remote server 156, anonline medical control physician 158, and/or other external users,devices and/or systems.

The mobile computing device 152 can be a portable device, such as atablet, that can be connected to the medical device 110 and/or otherdevices/systems, such as by an integrated patient monitoring and/ortreatment network. The mobile computing device 152 can receive, and/orobtain, patient information, such as from the medical device 110, andcan provide an interface for a user to interact with one or more of theconnected devices and/or systems, such as the medical device 110. Theuser can interact with the mobile computing device 110 to evaluate thepatient data, to provide instructions regarding patient treatment and/ormonitoring and/or for other functions and/or features. Additionally, themobile computing device 152, and/or other remote locations 150, canprovide, or assist, with analysis of the patient data, such asphysiological trend(s) analysis, that can be provided to the medicaldevice 110 and/or other users, devices and/or systems.

The medical director 154 can be an administrator that can assist withpatient monitoring and/or treatment decisions, such as on an individualpatient level or on a more generalized patient treatment protocol level.The medical director 154 can provide information and/or input to themedical device 110 to assist with the output by the medical device 110.For example, the medical director 154 can provide, or set,triggers/limits regarding physiological parameters to cause certaintreatment, or other, events to occur in response to specific, or ranges,of physiological parameter data. The provision or setting oftriggers/limits by the medical director can occur prior to deploying thedevice, and prior to the patient treatment event in which the devicewill be used.

The online medical control physician 158 can be provided patient data bythe system, allowing them to provide real-time guidance regardingpatient treatment and/or monitoring. Communication between the onlinemedical control physician 158 and a user of the medical device 110and/or the other medical devices 130, 140 can allow the online medicalcontrol physician 158 to provide instructions for monitoring and/ortreating the patient. Such communication can allow providers to bettertailor the resuscitation process and decision-making to the evolvingcourse and real-time status of the patient.

The remote server 156 can store and/or transmit received information,such as patient data, treatment protocol data and/or other data. One ormore external users, devices and/or systems can transmit and/or receivesuch information from the remote server 156. Additionally, the remoteserver 156 can include the ability to analyze the received patient datafor further analysis, such as trend analysis and/or other analysis, tofurther develop and/or refine patient treatment/monitoring protocols.For example, the remoter server 156 can analyze the collected patientdata to determine more effective patient treatment protocols that can beimplemented based on patient physiological parameter data.

FIG. 2 is an example physiological feedback system 200 that includes amonitoring module 210 and an external device 250. The external device250 can monitor and/or treat a patient while in communication, orconnected, with the monitoring module 210. The monitoring module 210 cansense and/or receive capnography and/or oximetry data of the patient tomonitor and/or assess an aspect of the physiologic state of the patient.The monitoring module 210 and/or the external device 250 can use thephysiologic state information to assess treatment efficacy, such ascardiopulmonary resuscitation (CPR) effectiveness. In response to theassessment, the monitoring module 210 and/or the external device 250 canadvise, or instruct, on further treatment and/or modification, oralteration, of treatment being administered, such as CPR.

In addition to assessing CPR effectiveness, the physiologic stateinformation of the patient can also be used to assess brain functionbased on the cerebral tissue oxygenation. During cardiac arrest, bloodflow is ineffective and oxygen deprivation of various tissues resultsdue to the lack of blood flow. CPR mechanically forces blood flow sothat oxygen deprivation is slowed. Brain and nervous tissue issusceptible to damage due to oxygen deprivation, so cerebral tissueoxygenation information can also be used to assess the magnitude ofoxygen deprivation in the brain. Trends in cerebral tissue oxygenationover time can also be used to assess the likelihood and/or magnitude ofdamage to the brain, and such information can in turn be used indecision-making regarding additional treatments and resuscitationefforts.

The monitoring module 210 can include physiological parameter sensors220, a processing module 230 and a communication module 240. Thephysiological parameter sensors 220 can be connected to and/orcommunicate with the monitoring module 210. Alternatively, the sensordata can be provided to the monitoring module 210 from one or moreexternal users, devices and/or systems. The physiological parametersensors 220 can include one or more oximetry sensors 222, one or morecapnography sensors 224, and one or more other physiologicalparameter(s) sensors 226, in some examples. The oximetry sensors 222 canprovide sensor data regarding tissue and/or blood oxygenation levels ofa patient which one or more oximetry sensors 222 are monitoring. Thecapnography sensors 224 can provide sensor data regarding the expiredCO2 levels of the patient. The other physiological parameter(s) sensors226 can provide sensor data regarding other physiological parameters,such as ECG data, non-invasive blood pressure data, pulse oximetry dataand/or other data regarding other physiological parameters.

The oximetry sensors 222 can include regional tissue oxygenation (rSO2)sensors 223 that can be placed on the patient to monitor oxygenation ofthe tissues underneath the sensors 223. One or more of the rSO2 sensors223 can be placed on the patient's head, such as on the patient'sforehead, to monitor cerebral tissue oxygenation, for example. The rSO2sensors 223 can be light-based sensors that include one or more lightemitters and detectors. The light emitters of the rSO2 sensors 223 canemit Near Infrared light having various light characteristics, such asone or more frequencies and/or wavelengths. The emission of NearInfrared light having multiple wavelengths can be used to senseoxygenation of blood at various depths beneath the rSO2 sensor 223. NearInfra-Red Spectometry (NIRS) can be used to calculate the oxygenationlevel of the blood in tissues under the rSO2 sensor 223. The NIRSprocessing can be performed by the monitoring module 210, and/or by anexternal device and/or system, to determine the blood/tissue oxygenationdata. Additionally, the NIRS processing can provide a broad measure ofblood oxygenation levels by providing oxygenation data that is acombination of venous and arterial blood oxygenations. The oximetrydata, such as provided by the rSO2 sensor 223 and processing of datatherefrom, can provide a measure of the patient's oxygenation stateand/or the balance between oxygenated and deoxygenated blood in thetissue being measured by the sensor.

The capnography sensors 224 measure fraction or partial pressure of CO2in gases in the airway, and from that airway CO2 signal end-tidal CO2(EtCO2) can be calculated. An airway CO2 sensor 225 can monitor the CO2expelled from the patient which can provide an indication of thepatient's CO2 levels and, since blood flow is the primary means oftransport of CO2 from the lungs, an indication of the amount of bloodflow occurring in the patient.

The processing module 230 can include a processor 232 and memory 234.The processor can analyze and/or evaluate data, such as received fromthe physiological parameter sensors 220 and/or the communication module240, and/or control one or more functions and/or features of themonitoring module 210. The memory 234 can store data, such as receivedfrom the physiological parameter sensors 220 and/or the communicationmodule 240, and/or instructions and/or processes for the processor 232to perform.

The communication module 240 can communicate with external devicesand/or systems, such as the external device 250, using one or morecommunication protocols and/or connections, such as Wi-Fi, the Internet,Bluetooth® and/or other protocols and/or connections. Data can betransmitted from and/or received to the tissue oxygenation module 210via the communication module 210. For example, the communication module240 can receive physiological parameter data and/or treatment data fromthe external device 250 and can transmit a tissue oxygenation valueand/or treatment instructions to the external device 250.

The external device 250 can include a CPR feedback module 260, aprocessing module 270 and a communication module 280. The externaldevice 250 can monitor the physiological state of the patient and/ormonitor patient treatment and provide instructions for additionaltreatment and/or modification of the current patient treatment.Monitoring a patient's physiological state and/or treatment can includecollecting physiological parameter data from the patient and/or datafrom the administration of treatment to the patient.

The CPR feedback module 260 can include a sensor(s) 262 to monitor oneor more parameters of CPR administration, such as compression rateand/or depth, and an output 264. The sensor 262 can be connected toand/or in communication with the CPR feedback module 260, to providedata regarding one or more CPR parameters. Alternatively, the CPRparameter data can be supplied to the external device 250 by anotherdevice and/or system that generates CPR parameter data. The output 264can provide information to a user regarding the administered CPR, suchas feedback, including an assessment of the administered CPR and/orinstructions to alter one or more parameters of the administered CPR.The output can communicate this information in a visual and/or audibleformat, such as by a display screen and/or a speaker. The user caninterpret the provided visual and/or audible output 264 to initiateand/or modify treatment of the patient.

The processing module 270 includes a processor 272 and memory 274. Theprocessor 272 can analyze and/or evaluate data, such as the tissueoxygenation value received from the tissue oxygenation module 210,and/or control one or more functions and/or features of the tissueexternal device 250. The memory 274 can store data, such as receivedfrom the CPR feedback module 260 and/or the communication module 280,and/or instructions and/or processes for the processor 274 to perform.

The communication module 280 can communicate with external devicesand/or systems, such as the tissue oxygenation module 210, using one ormore communication protocols and/or connections, such as Wi-Fi, theInternet, Bluetooth® and/or other protocols and/or connections. Data canbe transmitted from and/or received to the external device 250 via thecommunication module 280. For example, the communication module 280 canreceive tissue oxygenation data and/or treatment from the tissueoxygenation module 210 and can transmit CPR parameter data to the tissueoxygenation module 210.

In an embodiment, the monitoring module 210 can monitor tissueoxygenation levels of the patient using the oximetry sensor data 223,and/or levels of CO2 expired by the patient using capnography sensor 224data. From the collected oxygenation data, the monitoring module 210 cancalculate a tissue oxygenation value. From the collected capnographydata, the monitoring module can calculate EtCO2, providing an indirectassessment of pulmonary blood flow. The external device 250 can collectCPR parameter data, such as compression depth and rate, and can transmitthe collected CPR parameter data to the monitoring module 210. Themonitoring module 210 can use the received CPR parameter data, and/orthe calculated tissue oxygenation value, and/or the EtCO2 level, todetermine an effectiveness, or feedback, of the CPR being administered.In response to that determination, the monitoring module 210 can provideinstructions to the external device 250 to cause the administrator ofthe CPR to alter one or more of the CPR parameters and/or can providethe CPR feedback data to the external device 250 for output 264 and/orCPR instruction/alteration determination and output. In this manner, CPReffectiveness can be determined based on tissue oxygenation data, and/orairway CO2 data, and one or more parameters of CPR administration can bealtered in response to, and/or based on, the tissue oxygenation data.Alteration of the CPR administration can be done to increase or redirectblood flow and thereby assist with increasing tissue oxygenation levelswhich can assist with preventing damage, such as due to hypoxia, and/orcan improve the probability of achieving ROSC. In a further, oralternate, embodiment, the external device 250 can be a mechanical CPRdevice, such as a chest compression machine (CCM), and the operation ofthe mechanical CPR device can be automatically altered, or altered atthe discretion of the rescuer, based on the tissue oxygenation dataand/or the airway CO2 data.

While the monitoring module 210 and the external device 250, such as adefibrillator, patient monitor, monitor/defibrillator, mechanical CPRdevice and/or other medical treatment and/or monitoring device, areshown as separate elements, one or more features and/or functionality ofone or more of the tissue oxygenation module 210 and the external device250 can be combined and/or integrated with the other and/or anotherdevice.

FIG. 3 is an example physiological feedback system 300 that includes amedical device 310. The medical device 310 can include one or moresensors 320, a processing module 330, a communication module 340 and adisplay 350. The one or more sensors 320 can be coupled to a patient toreceive/sense data regarding the patient, such as one or morephysiological characteristics/parameters of the patient. Alternatively,or additionally, the medical device 310 can receive data regarding thepatient, such as physiological parameter data, from an external device,system and/or user. The medical device 310 can analyze, process and/orevaluate the sensed/received data to provide physiological feedbackregarding the patient, such as treatment metrics and/or other feedbackto guide treatment and/or monitoring of the patient.

Additionally, the medical device 310 can include input(s) regarding oneor more confounders that can obscure patient physiological data and/orinfluence patient monitoring/treatment. The confounder data can besupplied to the medical device 31 via the communication module 340and/or other inputs, such as by the sensors 320. Example confounders caninclude the administration of medications, administration of treatments,rescuer observations/inputs, and/or other inputs. The confounders, suchas medication/treatment administration, can cause temporary changes inthe physiological data of the patient that might obscure the patient'sactual physiological state and/or trend thereof. Confounders, such asrescuer observations/inputs, can alter weighting/importance of one ormore physiological parameters due to the observation/input. For example,a patient may exhibit signs of consciousness while in cardiac arrest andreceiving CPR, which is uncommon but can indicate that cerebral bloodflow and cerebral tissue oxygenation are high enough to support a degreeof consciousness. Typically, the assessment of a patient in cardiacarrest assumes the patient is unconscious, so the observation ofconsciousness during such an event can be input to provide additionalinformation that can be considered when assessing the patient, wheninterpreting other data from the resuscitation event, and/or whendetermining further patient monitoring/treatment.

The sensor(s) 320 can be placed on, or near, the patient and connectedto, or in communication with, the medical device 310 to provide sensordata indicative of one or more physiological parameters of the patient,a physiological condition of the patient, treatment administered to thepatient and/or other data regarding the patient. In the example of FIG.3, the sensors 320 include one or more cardiopulmonary resuscitation(CPR) sensors 322 and/or one or more physiological parameter sensors326. The CPR sensors 322 can provide data regarding the administrationof CPR, or lack thereof. The data can include measurements of one ormore CPR variables, characteristics of the CPR administration and/orother data regarding the administration of CPR. The physiologicalparameter sensors 326 can provide data regarding one or morephysiological parameters of the patient.

The CPR sensors 322 can be placed on and/or near the patient and caninclude a position sensor 323, an impedance sensor 324 and/or othersensors to measure, monitor and/or assess the administration of CPR to apatient. The position sensor 323 can include one or more elements thatare placed on the patient to which CPR is being administered, on theperson of a user administering CPR to the patient, and/or placedproximal the patient, such as above the patient, on a surface near thepatient, beneath the patient and/or other patient adjacent locations.One or more signals can be generated by the position sensor 323 that canbe indicative of one or more parameters/characteristics of theadministered CPR, such as a rate of compressions, the depth ofcompressions, the number of compressions and/or otherparameters/characteristics related to the administration of CPR to thepatient. The impedance sensor 324 can measure a transthoracic impedanceof the patient, such as by a pair of electrodes placed on the patient,and the measured data can be indicative of CPR administration since thetransthoracic impedance of the patient changes in response toadministered compressions.

The physiological parameter sensors 326 can include a regional tissueoximetry (rSO2) sensor 327, such as to measure cerebral tissue oximetry,an airway CO2 sensor 328, from which end-tidal CO2 (EtCO2) can becalculated, an electrocardiogram (ECG) sensor 329 and/or otherphysiological parameter sensors. The sensor signals generated by therSO2 sensor 327 and/or the airway CO2 sensor 328 can be indicative ofthe level of blood flow in the patient. Such data can be used to assessand/or analyze the physiological state of the patient. Additionally,such physiological parameter data can provide information regardingpotential future patient physiological states, provide information fortreatments and/or interventions, and/or other information for use inmonitoring and/or treating the patient. Further, the collectedphysiologic and/or patient data can be used for pattern, and/or other,analysis to aid in developing and/or refining the plan for ongoingpatient treatment, monitoring and/or assessment.

The ECG sensor 329 can include two or more electrodes that are placed onthe patient and provide sensed data to the medical device 310.

Reception of sensed data, from the sensors 320, by the medical device310 can be via wired and/or wireless connection(s). In an embodiment inwhich the transmission of data is via a wireless connection, the senseddata and/or the connection can be encrypted/secured to protect theintegrity of the transmitted sensor data. Additionally, the sensed datacan be communicated to the medical device 310 from one or more otherdevices and/or systems that monitor/sense physiological parameter dataof the patient.

The processing module 330 can include a processor 332 and memory 334.The processing module 330 can control one or more functions and/orfeatures of the medical device 310. Additionally, the processing modulecan receive various data/information, such as from the sensors 320and/or a user, device and/or system, for collection and/or analysis. Thecollection and/or analysis of data by the processing module 330 canassist with patient assessment, treatment and/or monitoring. Further,such data can also be processed for multiple patients to determinetrends and/or patterns that can assist with future patient assessment,monitoring and/or treatment. The processing module 330 can also collectand store information regarding patient instances, such as assessment,monitoring and/or treatment data, that can be transmitted, or provided,to a user, device and/or system upon conclusion of the patient instance.

The communication module 340 can transmit and/or receive informationfrom/to the medical device 310 and one or more external devices and/orsystems. The communication module 340 can communicate with the one ormore external devices and/or systems via one or more communicationprotocols and/or connections, such as Bluetooth®, Wi-Fi, the Internetand/or other communication protocols and/or connections. Communicationsto and/or from the communication module 340 can be via a securecommunication channel and/or can be encrypted, to preserve theintegrity, or security, of the communications. In an example, one ormore of the sensors 320 can be part of an external device/system thattransmits sensed data to the medical device 310 via the communicationmodule 340.

The display 350 can provide information in a visual format to a user,device and/or system. To provide the information, the display 350 caninclude one or more screens, lights and/or other visual indicators, todisplay, or provide, information in a visual format. The display 350, orportion thereof, can also be configurable allowing the format and/orother characteristics of the display to be altered, such as in responseto the user and/or by the processing module 330. The configurability ofthe display 350, or portion thereof, can allow the display 350 toprovide relevant information in a more accessible manner, such as byhighlighting priority information more than other information displayedby the display 350.

Example visual formats the display 350, or portion thereof, can displayinformation in a numerical format 352, a categorical format 354 and/or asymbolic format 356. The numerical format 352 can include displayingnumerical values, such as measurements of physiological parameters, onthe display 350. The categorical format 354 can include displayingand/or highlighting a category, such as a negative, neutral and/orpositive category for a variable like a physiological parameter. Thecategorical format 354 can also be represented by one or more colorsthat can change depending on the value of the category. For example, thecolor green associated with a category can indicate a positive andsimilarly, yellow can indicate neutral and red can indicate negative.Additionally, or alternatively, the categories of the categorical formatcan be displayed as variable indicators, such as a changing bar that canmove or expand based on the measurement/value of the category. Thevariable indicator can also include color associations, such as thosepreviously discussed. The symbolic format 356 can include graphicaland/or textual representations of data, such as a text message and/or agraph. The format(s) of the display 350 are presented to aid in thespeed and accuracy of determining the information represented, ordisplayed, thereon. Further, the display 350 can alter the format ofinformation displayed based on the importance of the information. Forexample, information that is of lesser importance can be representedcategorically 354, such as to reduce the necessary area required for thedisplay of such information, the display format can change if theinformation becomes more relevant or important, such as to a numerical354 and/or larger format to highlight the importance of the informationand/or that the importance of such information has changed from aprevious state. Again, such functionality assists with presenting therelevant information in a format that assists with the efficient andaccuracy determination of the displayed information.

FIG. 4 is an example physiological feedback method 400. At 402, sensordata is received. In an example, the sensor data can include dataregarding physiological parameters of a patient, such as regarding theirend-tidal CO2 levels, their tissue oximetry levels, and/or their heartrhythm assessed from the sensed ECG data, and/or data regarding CPRadministration, such as transthoracic impedance and/or CPR positionaldata. At 404, CPR administration can be identified in the receivedsensor data, such as at 402. Identification of CPR administration can bedetermined from various sensor data, such as transthoracic impedancedata and/or CPR sensor data. The identification of CPR administration,such as at 404, can include identifying the onset, or beginning, of CPRadministration and/or one or more characteristics of the administeredCPR, such as a rate of compressions, a depth of compressions and/orother characteristics.

At 406, optionally, continuous blood pressure measurement data can bereceived. The continuous blood pressure measurement data can becollected using a non-invasive and/or an invasive system/method ofobtaining blood pressure measurement data. The collected blood pressuredata can include an arterial diastolic blood pressure and/or other bloodpressure measurements. The blood pressure measurement data can bereceived from a user, device and/or system.

At 410, optionally, medication treatment data can be received.Medication treatment data can include identification of medicationsadministered to the patient and can also include additional informationregarding the medication, such as a dosage, manner of administration,time of administration and/or other information/data regarding themedication and/or its administration. The medication treatment data canbe received from a user, device and/or system. For example, certainmedications, such as sodium bicarbonate, that are typically administeredin response to cardiac arrest can cause temporary changes in one or morephysiological parameters, such as EtCO2 in the example of sodiumbicarbonate. The increased EtCO2 due to the sodium bicarbonateadministration could be incorrectly assumed to be due to increased bloodflow in the patient, however, by providing medication data, the process400 can account for this temporary increase in EtCO2. This accountingcan be done by comparing the increase in the EtCO2 to otherphysiological parameter data, such as oximetry data, to determine if acommensurate effect is also observed that would be indicative of aphysiological state change in the patient, rather than a change due to aconfounder, such as the medication administration. Similarly, otherpatient treatments, such as intubation, can cause confounding effectsthat the process 400 can account for and/or consider in deriving theindex. Additionally, the process 400 can account for other confounders,such as environmental and/or contextual confounders, that can be inputto the process 400, such as by a user, device and/or system.

At 408, physiological parameter data can be received. The receivedphysiological parameter data can include capnography data, such as EtCO2data/measurements, and also can include rSO2 data. Other and/oradditional physiological parameter data can also be received, such asECG data. At 412, a trajectory and/or level of rSO2 andEtCO2measurements can be determined. Determination of the trajectory ofthe rSO2 and EtCO2 measurements can include analyzing/evaluating thereceived physiological parameter data, such as from 408. Based on theanalysis/evaluation, a trajectory for one or both the rSO2 and EtCO2measurement data can be determined, such as a downward, or declining, oran upward, or improving, trajectory. Such trajectory information can beindicative of a patient's improving, stable, or declining physiologicalcondition. The levels of rSO2 and/or EtCO2 can be expressed aspercentages and/or other forms. Similar to the trajectory, the levelinformation can be indicative of the patient's improving, stable, ordeclining physiological condition. Additionally, the trajectory and/orlevels of the rSO2 and EtCO2 measurements provide an indication of thepatient's current physiological condition. Such information can be usedto assess the current treatment the patient may be receiving and/or ifchanges should be made to the treatment.

At 414, using the trajectory and/or level data of 412, an index of theeffectiveness of treatment, such as blood flow during CPR administrationto the patient, can be derived. This effectiveness index providesinformation regarding the patient's physiological response to theadministered CPR. Using the effectiveness index, the administration ofCPR can be evaluated to determine if changes to the administration ofthe CPR should be made. At 416, the derived effectiveness index can bedisplayed, such as on a display of a medical device. A user, such as theuser administering CPR, can review the derived index to modify or alterthe administration of CPR. Alternatively, and/or additionally, CPRadministration modifications and/or alterations can also be displayedwith the derived index. The displayed modifications and/or alterationscan be based on the received data, such as at 402, 406, 408 and/or 410,and can include modification and/or alteration of one or more of thecharacteristics of the administered CPR. Additionally, the modificationsand/or alterations can include other intervention instructions, orsuggestions, such as the administration of medications and/or othertreatments.

The derived effectiveness index can be continuously modified and/orupdated based on received data, such as physiological parameter data. Inan example, CPR parameter measurement data, such as compression rate,compression depth, compression recoil adequacy, ventilation rate,ventilation tidal volume and/or other CPR parameter(s), orcharacteristic(s), measurement data, can be received in substantiallyreal-time. The real-time acquisition of such data allows the receivedCPR parameter measurement data to be correlated to other received dataand the derived effectiveness index can be updated and/or modified basedon the correlated data. The correlation of the data can allowdeterminations regarding changes in the CPR administration and theireffect on other measured physiological parameter data, such as the rSO2and/or EtCO2.

Administered medications can also affect the received physiologicalparameter data. The received medication treatment data of 410 can becorrelated to the received physiological data and the derivedeffectiveness index can be updated and/or modified based on thecorrelated data. For example, administration of a medication can causeimprovement in one or more of the rSO2 and/or EtCO2 measurements.Correlation of medication administration to the improvement in thephysiological parameter measurement data can allow the derivedeffectiveness index to indicate that such improvement is possiblytemporary or possibly greater improvement that an actual improvement inthe physiological condition, or state, of the patient. In addition toadministered medications, the derived effectiveness index can also beupdated and/or modified based on treatment administration, such as anintubation of the patient. The treatment administration can also becorrelated with other physiological parameter measurements and thederived effectiveness index can be updated and/or modified based on suchcorrelated data. The correlation of administration of treatments and/ormedications with physiological data changes can assist with identifying,and/or removing, confounders and their effects from the derivedeffectiveness index. The derived effectiveness index is therefore morerepresentative of the physiological state of the patient and/or trendsthereof.

The correlation of events, such as medication administration, changes tothe CPR administration and/or treatment administration, to thephysiological parameter measurement data can allow the derivedeffectiveness index to more accurately, or more truly, represent theeffectiveness of blood flow, or a physiological state, of a patientduring CPR administration. The derived effectiveness index includingsuch correlation information can be more useful in determining furthertreatment of the patient, since more accurate assessments of thepatient's physiological condition can be made by a user, device and/orsystem.

The derived effectiveness index can be displayed at 416 in one or moreformats, such as a numerical, categorical and/or symbolic format. As anumerical format, the derived effectiveness index can be displayed as avalue, such as from 0-10. As a categorical format, the derivedeffectiveness index can be displayed as a categorical value, such as“worsening,” “stable,” or “improving.” As a symbolic format, the derivedeffectiveness index can be displayed as a pictograph and/or textualmessage.

In an example in which the received data is indeterminate and/or unableto be accurately correlated, the derived effectiveness index may not bedisplayed. Rather than displaying the derived effectiveness index, anotification can be displayed to indicate the derived effectivenessindex is indeterminate. Typically, when the derived effectiveness indexis indeterminate, often the physiological state of the patient isimproving in response to the administered treatment and that is why theprocess 400 is unable to accurately correlate the administration oftreatment and/or its effects. In an example, an indeterminate indicationcan be accompanied by instructions to continue the current treatmentuntil the derived effectiveness index is no longer indeterminate and anassessment of the patient can be made. Once the derived effectivenessindex is no longer indeterminate, the display can remove theindeterminate notification and can display the derived effectivenessindex.

FIG. 5 is an example physiological feedback method 500. Thephysiological feedback method 500 can provide determination ofindications of Return of Spontaneous Circulation (ROSC) in a patient.CPR administration to a patient can be altered, and/or discontinued,based on a determination of ROSC. The continued administration of CPR toa patient having ROSC can induce fibrillation in the patient, and/orotherwise contribute to the patient deteriorating back into cardiacarrest. As such, the determination of ROSC is important factor inmonitoring and/or treating the patient, such as the determination totransport the patient to a hospital or other healthcare facility.

At 502, an index of the effectiveness of blood flow during CPR can bederived, such as by the method 300 of FIG. 4. At 504, the index data canbe analyzed and at 506 patterns and/or thresholds indicative of ROSC canbe determined from the index data. In addition to the index data, thedetermination of patterns/thresholds indicative of ROSC can, optionally,also be based on received physiological parameter data at 510. Thereceived physiological parameter data can include an ECG signal. The ECGsignal can be filtered to remove CPR induced artifacts. The optionalphysiological parameter data and the index data can be evaluated forpatterns and/or thresholds indicating that the patient may have ROSC. Ifsuch a determination is made, an alert can be output at 508. The outputcan be an audible and/or visual notification to a user, such as a CPRadministrator, that ROSC may have occurred in the patient.

In addition to optionally receiving physiological parameter data at 510,the method 500 can also optionally include analyzing the physiologicalparameter data for trends and/or trajectories at 512. Thetrend/trajectory information can be used to further refine, updateand/or modify the index at 502. In this manner, the patient can becontinuously and/or regularly assessed for potential ROSC.

In an example, the physiological parameter data can include an ECGsignal and the measurements and/or trajectories of the patient's heartrate and/or QRS complex morphology can also be used to derive the indexat 502. Further, a transthoracic impedance signal can also be includedin the received physiological parameter data. Measurements and/or trendsof the transthoracic impedance signal, and/or QRS-synchronous featurescontained therein, can be used to derive the index at 502. One or bothof the ECG and transthoracic impedance signal can be used to derive theindex and assist with determination of potential ROSC in the patient. Ifan invasive arterial pressure signal is available, this signal can beused by itself or in combination with other physiological signals toderive the index. In particular, presence of blood pressure pulses notcorrelated with chest compressions indicates a high, or increased,likelihood of ROSC.

FIG. 6 is an example physiological feedback method 600 that derives anindex suggestive and/or indicative of hemodynamic and/or circulatoryadequacy. At 602, CPR administration is identified, such as by one ormore CPR and/or transthoracic impedance sensors, as having beenperformed and is now not being performed. At 608, a determination thatthe patient has achieved ROSC is made. The determination at 608 can bebased on a received indication of ROSC at 604, such as by a user inputand/or based on received physiological data at 606. The user input canbe through a device performing the method 600 and/or from an externaldevice/system coupled to a device performing the method 600. At 610, anindex suggestive and/or indicative of the hemodynamic and/or circulatoryadequacy of the patient can be derived. The index can be derived fromphysiological data received at 606. The received physiological data caninclude rSO2 and EtCO2 measurement data from which levels and/ortrajectories can be determined. The determined levels and/ortrajectories of the rSO2 and EtCO2 data can be used to derive the indexat 610. The process 600 can be iterative and/or repeated, with thederived index being updated and/or modified as further physiologicaland/or other data is received.

At 616, the derived index can be optionally displayed until CPR isresumed. The derived index can be displayed as a numerical value, suchas a value on a range of values; a categorical value, such as “stable,”“declining,” or “improving;” and/or as a symbolic value, such as atextual and/or pictorial notification.

At 612, an optional determination of hemodynamic and/or circulatorydeterioration can be made. The determination can be made based on thederived index of 610 and/or based on levels/trajectories of the rSO2 andEtCO2 measurements. A specific point and/or magnitude of thedeterioration can be indicative of potential, or occurring, re-arrest inthe patient.

At 614, an optional alarm can be triggered based on hemodynamicdeterioration. Hemodynamic deterioration can include the decrease inblood flow through the patient, a decrease in tissue oxygenation and/ora decrease in other hemodynamic parameters/characteristics. Suchdeterioration can be an indication that a physiological state of thepatient is potentially about to decline and/or that intervention isrecommended, and/or required, to prevent and/or reduce the hemodynamicdeterioration. The alarm can be based on one or more thresholds and canbe escalating based on the one or more thresholds. The thresholds can bepredetermined, user provided and/or a combination thereof. Additionally,the alarm can be indicative of the degree of hemodynamic deteriorationdetected and/or determined. In response to the alarm, a user monitoringand/or treating the patient can provide intervention, if needed.

FIG. 7 is an example physiological feedback method 700 that provides asummary of inputs that triggered a pattern detection to assist withidentification of a cause, such as a confounder, and/or consequences ofa change in one or more physiological parameters of a patient, such as achange in the physiological state, or trend, of the patient. At 702,rSO2 and EtCO2 data is received and at 704 CPR parameter data, such ascompression rate and depth, is received. The received rSO2 data caninclude tissue oxygen saturation information and can also include otherinformation, such as tissue hemoglobin concentration, tissue bloodvolume index information, and/or similar information. At 706,optionally, confounder data, such as medication data, includingidentification, dosage, administration time and/or administrationmethod, can be received. The confounder data input is environmental,contextual and/or medication data that can have a temporary, observableand/or detectable, effect of the patient's physiological state. Input ofsuch confounder data allows the process 700 to account for thesetemporary effects so that the feedback provided is more indicative ofthe actual physiological state of the patient and/or trends thereof. At708, change patterns in two or more of the monitored data, such asreceived at 702, 704 and/or 706, can be detected. The detection can bebased on correlating pre-configured/pre-determined change patterns withchanges in the received two or more monitored data, such as the rSO2 andEtCO2 signals. The pre-configured change patterns can include a rate ofchange and/or other time-variant characteristics that can be correlatedwith the received physiological and/or other patient data. Optionally,the pre-configured and/or pre-determined change patterns can be userconfigurable, allowing a user or other to specify the change patterns totrigger detection of changes in the received data.

At 710, the summary of inputs, such as the inputs that triggered thepattern detection/correlation, and CPR trends can be displayed. Forexample, concurrent declines in the rSO2 and EtCO2 can trigger changepattern detection. In response, the rSO2 and EtCO2 data can bedisplayed. The displayed data can optionally include highlighting and/orother notification of the change pattern. Also displayed can be CPRtrend data, such as changes in compression rate, depth and/or other CPRparameters. The concurrent display of such information can allow for acause-and-effect determination. That is, it can be determined iftreatment, such as CPR and/or medication administration, is responsible,or caused, changes in the physiological parameter data and/or thephysiological parameter consequences dye to the change in treatment. Auser monitoring and/or treating the patient can review the displayedsummary to determine further changes to the treatment of the patient.Alternatively, evaluation of the summary can be performed by a deviceand/or system, and instructions and/or suggestions for/regarding thepatient treatment can be provided.

The summary 710 can be displayed as a popup, or overlay, on a medicaldevice, such as a monitor and/or defibrillator, being used to monitorand/or treat the patient. Alternatively, the summary can be provided ona device that is in communication with the treatment and/or monitoringdevice/system coupled to the patient. Example devices can includetablets and/or other computing devices communicating with the patienttreatment/monitoring device/system via a patient care reporting and/orevent recording system/software. The summary can be temporarily orcontinuously displayed and can also be configurable by a user to alterone or more characteristics of the display.

FIG. 8 is an example method 800 for detecting ROSC. At 802, rSO2 andEtCO2 data can be received and at 804, the received data can be analyzedand/or changes in the data can be tracked. Based on the analysis and/ortracked changes, various indications of ROSC can be made. At 806, basedon the analysis and/or change data, an increase of, for example, 10% orgreater in the rSO2 of the patient in a minute or less can be indicationthat ROSC is likely at 808. If no such change is detected and/ordetermined, the process 800 can return to receiving further capnographyand/or tissue oximetry data for further analysis and tracking. At 810,an increase, within a short time period, in the patient's EtCO2 ofgreater than, for example, 10 mmHg combined with an increase of, forexample, greater than 5% in the patient's rSO2 can be indicative oflikely ROSC at 812. If no such changes are detected and/or determined,the process 800 can return to receiving further capnography and/ortissue oximetry data for further analysis and tracking. At 814, a suddendecline in EtCO2 of, for example, more than 10 mmHg and a decline ofgreater than, for example, 10% in sRO2 can indicate that the patient'sreturn to a state of cardiac arrest, or re-arrest, is possible at 816.Threshold values, such as values higher or lower than those provided inthese examples, may be implemented in the system, and may also be ableto be configured by a user of the system. The possible re-arrestindication can provide a warning to allow treatment to be altered toprevent and/or prepare for the potential re-arrest of the patient. If nosuch changes are detected and/or determined, the process 800 can returnto receiving further capnography and/or tissue oximetry data for furtheranalysis and tracking. The repeated reception and analysis ofcapnography and/or tissue oximetry data can assist with the detection offuture physiological states of the patient, such as the patientexperiencing a likely ROSC and/or a possible re-arrest. The predictivenotifications can allow for altered patient monitoring and/or treatmentbased on the notification.

Additionally, the process 800 can include input, by a user, deviceand/or system, of patient observations. In an embodiment, the inputobservations can alter one or more of the thresholds and/or decisions ofthe process 800. For example, a rescuer can input that a patient isexhibiting signs of consciousness during a cardiac arrest resuscitationeffort. Additionally, other supplied inputs or observations can beassessed for their impact on potential rearrest and/or ROSC of thepatient and can alter one or more of the decisions and/or thresholds ofthe process 800.

FIG. 9 is an example method 900 of determining a measure, such as amagnitude, of an ischemic injury to a brain. Ischemic injury to thebrain is caused by the brain being deprived of oxygen, such as can beexperienced during a cardiac arrest. The measure of ischemic injury tothe brain of a patient can be used in making treatment decisionsregarding the patient. In an embodiment, a patient in cardiac arrest canexperience brain hypoxia that causes ischemic injury to the brain. Theischemic injury can be assessed and/or quantified using the method 900and further treatment decisions can be made. For example, for patientswho remain in cardiac arrest for a prolonged interval, but in whom thedetermined aggregate ischemic exposure, or ischemic injury, to thepatient's brain nevertheless indicates a reasonable probability of thebrain to recover from such injury, treatment decisions can be made toprovide further interventional treatment. The measure of aggregateischemic exposure, or ischemic injury, can for example be based upon anassessment of whether the cerebral tissue oxygenation level of thepatient was above a certain threshold level for at least a certainthreshold percentage of the elapsed resuscitation effort.

At 902, rSO2 data can be received. Such rSO2 data can provide a measureof the balance of supply and demand of oxygen in the brain tissues. At904, the rSO2 data can be analyzed relative to time. The duration ofrSO2 levels and changes in rSO2 levels can be indicative of oxygensupply and/or demand to/of the patient's brain. At 906, a determinationof the measure of the ischemic injury to the patient's brain can bemade. The determination can be based on the treatment session to thatpoint and cerebral tissue oxygenation levels during that time. Forexample, the determination can be made that the cerebral tissueoxygenation level of the patient was above a level for at least apercentage of the treatment session, and as such the measure of ischemicinjury is a first value based on the collected cerebral tissueoxygenation data during the treatment session. Various cerebral tissueoxygenation level and percentage of treatment session associations canbe used to determine the measure of ischemic injury at 906. Suchdetermination can be made on the received rSO2 data for the patient,other received patient physiological parameter data, and/or, optionally,outcome and rSO2 data from other patients. The outcome and rSO2 data forother patients can be collected and analyzed to refine the model,process and/or algorithm used in determining the measure of the ischemicinjury to the patient's brain. In this manner, the determinationaccuracy can be further refined and updated, such as in response to newand/or updated patient interventions and/or treatments. Along with theoutcome and rSO2 data, other physiological parameter and/or patient datacan be collected for analysis and/or correlation to assist with refiningthe determination. Optionally, the determination at 906 can beindeterminate. The indeterminate determination can be indicative thatthe cerebral tissue oxygenation data of the patient is not sufficientand that other physiological data should be used to determine themeasure of ischemic injury.

FIG. 10 is a method 1000 for presenting cerebral and/or other tissueoximetry, such as rSO2, and/or other capnography/oximetry data, inconjunction with other patient information to assist with patientmonitoring and/or treatment. Such display can assist with determiningcause-and-effect relationships between treatments and/or interventionsand a patient's physiological response to the same.

At 1002, rSO2 data can be received. At 1004, a display scale can becalibrated based on the rSO2 data. Calibration of the display caninclude calibration based on a timing, such as sampling rate, of therSO2 data and/or a magnitude, such as levels/percentage, of the rSO2data. In an example, the calibration of the display can includecondensing the time scale in order to display a history of events thatoccur on a minute time scale, such as changes and/or initiation oftreatments/interventions, rather than a second-to-second time scale asmight be used to collect rSO2, and/or other physiological, data. At1006, intervention data, such as changes to treatment and/or initiationof treatment, and other physiological data, such as other capnographyand/or oximetry data, can be received. Changes to treatment can includechanges to CPR administration, such as changes to compression rateand/or depth, and can include changes to ventilation of the patient.Additionally, or alternatively, the changes to treatment can include theadministration of medication and/or other treatments such asdefibrillation shocks. At 1008, the rSO2 and the receivedintervention/physiological data can be presented on the calibrated scaleof the display. The display of such information can allow a usertreating the patient to determine the effect of treatment and/ortreatment changes on the physiological state of the patient, such as animprovement or decline in the patient's physiological state. The displaycan provide information that can assist with further treatment and/ormonitoring of the patient.

The features disclosed in the foregoing description, or the followingclaims, or the accompanying drawings, expressed in their specific formsor in terms of a means for performing the disclosed function, or amethod or process for attaining the disclosed result, as appropriate,may, separately, or in any combination of such features, be used forrealizing the invention in diverse forms thereof.

1-29. (canceled)
 30. A medical device comprising: an airway sensorconfigured to detect a level of carbon dioxide expelled from an airwayof an individual; an oximetry sensor configured to detect a bloodoxygenation level of the individual; and a processor configured to:determine a threshold based on the level of carbon dioxide expelled fromthe airway of the individual; determine that the blood oxygenation levelof the individual exceeds the threshold; and determine that the patienthas experienced return of spontaneous circulation (ROSC) based ondetermining that the blood oxygenation level of the individual exceedsthe threshold.
 31. The medical device of claim 30, wherein the oximetrysensor comprises a regional tissue oxygenation (rSO₂) sensor.
 32. Themedical device of claim 30, further comprising: a screen configured tovisually output an indication of the ROSC; and a speaker configured toaudibly output the indication of the ROSC.
 33. A medical devicecomprising: a first sensor configured to detect a first physiologicalparameter indicating a hemodynamic adequacy of an individual, the firstphysiological parameter being correlated with a confounder; a secondsensor configured to detect a second physiological parameter indicatingthe hemodynamic adequacy of the individual, the second physiologicalparameter being non-correlated with the confounder; and a processorconfigured to: determine, based on the first physiological parameter, athreshold; compare the second physiological parameter to the threshold;and based on the comparison of the second physiological parameter to thethreshold, determine a condition of the individual, wherein thecondition comprises a return of spontaneous circulation (ROSC) of theindividual, an effectiveness of cardiopulmonary resuscitation (CPR)performed on the individual, or a risk of cardiac re-arrest of theindividual.
 34. The medical device of claim 33, wherein the firstphysiological parameter or the second physiological parameter comprisescarbon dioxide expelled from an airway of an individual.
 35. The medicaldevice of claim 33, wherein the first physiological parameter or thesecond physiological parameter comprises a blood oxygenation level ofthe individual.
 36. The medical device of claim 35, wherein the firstsensor or the second sensor comprises a regional tissue oxygenation(rSO₂) sensor configured to detect the blood oxygenation level of theindividual.
 37. The medical device of claim 33, wherein the confoundercomprises a medication administered to the individual or a treatmentadministered to the individual.
 38. The medical device of claim 33,further comprising: a display configured to visually output anindication of the condition.
 39. The medical device of claim 33, furthercomprising: a speaker configured to audibly output the indication of thecondition.
 40. The medical device of claim 33, further comprising: atransmitter configured to transmit an indication of the condition of theindividual to an external device.
 41. A device comprising: a processor;and memory storing instructions that, when executed by the processor,cause the processor to perform operations comprising: determining athreshold based on a first physiological parameter indicative of ahemodynamic adequacy of an individual, the first physiological parameterbeing correlated with a confounder; comparing the threshold to a secondphysiological parameter indicative of the hemodynamic adequacy of theindividual, the second physiological parameter being non-correlated withthe confounder; and based on the comparison of the second physiologicalcomparison to the threshold, determine whether the individual isexperiencing return of spontaneous circulation (ROSC).
 42. The device ofclaim 41, further comprising: a receiver configured to receive dataindicative of the first physiological parameter or the secondphysiological parameter.
 43. The device of claim 41, wherein the firstphysiological parameter or the second physiological parameter comprisescarbon dioxide expelled from an airway of an individual.
 44. The deviceof claim 41, wherein the first physiological parameter or the secondphysiological parameter comprises a blood oxygenation level of theindividual.
 45. The device of claim 41, wherein the confounder comprisesa medication administered to the individual or a treatment administeredto the individual.
 46. The device of claim 41, further comprising: adisplay configured to visually output an indication of whether theindividual is experiencing ROSC; or a speaker configured to audiblyoutput the indication of the individual is experiencing ROSC.
 47. Thedevice of claim 41, wherein the operations further comprise: based onthe comparison of the second physiological comparison to the threshold,determining an effectiveness of cardiopulmonary resuscitation (CPR)performed on the individual.
 48. The device of claim 47, furthercomprising: a transmitter configured to transmit, to an external device,a signal based on whether the individual is experiencing ROSC or theeffectiveness of the CPR performed on the individual.
 49. The device ofclaim 48, wherein the external device comprises a mechanical CPR device.